Method of measuring the hardness of abrasive disks



III/I A ia Jan, 28,1936.

K. GEPPERT METHOD" OF MEASURING THE HARDNESS OF ABRASIVB DISKS Filed Oct. 31, 1934 .51 veafd Karl Gay mp2 far i MM Patented Jan. 28, 1936- UNITED STATES PATENT OFFICE Methods of measuri disks, such as for exam the impact method, th

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METHOD or MEASURING THE HARDNESS 0F ABRASIVE DISKS Karl Geppert, Schweinfurt- Application October In 1 Claim.

mg the hardness of abrasive the scratching method, ping method and the eady known but they e. 1

This invention enables the result of the test to be of accuracy. A thi terial, 10 board size is pointe a defi d conical impact abrasive disk. The depth on the hardness of the abrasiv ing hole .in the plate forms of the abrasive disk being t obtained with certainty to a very high degree 11 plate of perforatable masuch as for example, sheet metal, cardor pasteboard, or the like, of any desired laid on the abrasive disk to be tested. A pin, which is given one or nite number of blows of perforates the plate and pe uniform intensity netrates into the enetration depends e disk. The resulta qualitative record ested in that the'diofp meter can be taken as the.

pective view of the assemrrying out the invention;

ctional view of said ason-the-Main, Gergelfischer Erste Autogelfabrik vorm. Friedrich on-the-Main, Germany 31, 1934, Serial 'No. 750,901 Germany November 3, 1933 Fig. 3 a plan view of a perforated plate used.

In Figures 1 and 21's shown an abrasive disk a, a thin plate b to be perforated and a punch or impact pin 0 with its conical point.

Both Figs. 1 and 2 show the plate b in position 5 on top of the abrasive disk a with the punch c after a blow has been applied thereon so that its point has penetrated the plate b and entered the disk a. A certain relation is thus established between the depth of penetration in the disk a 10 and the diameter of the hole produced in the plate b. The diameter of the resultant hole in the plate c, Fig. 3, will thus indicate the hardness of the abrasive material in disk a.

What I claim is:

A method of measuring the hardness of abrasive disks or plates consisting in applying a sheet of perforatable material to the surface of said disk a1 impact pin through driving force, and meas KARL GEPPERT.

perforation in the sheet. 

